JP2003037388A - Electromagnetic wave shielding material and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic shielding material that has superior light transmissivity and visibility and, at the same time, is excellent in electromagnetic wave shielding effect. SOLUTION: This electromagnetic wave shielding material is manufactured by blackening a meshed single metal foil obtained by meshing metal foil both surfaces of which are made to be lustrous and rough, respectively, and rust-proof treated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shield material which is provided on a visual surface of an electronic device or the like and blocks transmission of electromagnetic waves from inside the device to the outside or from outside the device to the inside. The present invention also relates to a manufacturing method suitable for manufacturing the electromagnetic wave shielding material.

[0002]

2. Description of the Related Art In recent years, an electromagnetic wave shield material has been attracting attention as one of means for blocking an electromagnetic wave emitted from an electronic device. As an electromagnetic wave shielding material, a metal mesh, which is a mesh of metal wires typified by a sieve for classifying fine particles, so-called a wire mesh is known. Also,
For example, there is also known an electromagnetic wave shielding material which uses a resin fiber such as polyester as a base material and uses a metal mesh obtained by coating the base material with a metal such as copper or nickel by a means such as electroless plating.

Some of these electromagnetic wave shield materials are applied to displays such as plasma displays. In that case, it is required to be as thin as possible, and it is necessary to achieve a good balance between light transmittance and electromagnetic wave shielding properties contradictory thereto. As an electromagnetic wave shielding material satisfying such requirements, the present inventor Japanese Patent Laid-Open No. 11-350168 discloses a metal foil mesh using a photoresist method. The present inventor also reported in Japanese Patent Application No. 2001-76183 a method for suitably producing a single metal foil mesh which is not limited to the constitution in which it is adhered to a substrate via an adhesive. When these metal foil meshes are used as electromagnetic wave shielding materials for displays, the visibility of the displays is improved by blackening the viewing surface.

[0004]

However, in the case of the above-described simple metal mesh, when the blackening treatment is performed, the entire metal mesh is blackened, for example, the surface of the copper mesh is oxidized to form an oxide film. Since the structure is covered, there is a problem in that the conductivity of the metal mesh is lowered and the earth cannot be sufficiently grounded, which causes a reduction in the electromagnetic wave shielding effect.

Therefore, it is an object of the present invention to provide an electromagnetic wave shielding material having excellent light transmittance and visibility and an excellent electromagnetic wave shielding effect, and a method for producing the same.

[0006]

The electromagnetic wave shielding material of the present invention is characterized in that it has a blackening treatment layer on the surface of a metal foil mesh which is composed of a glossy surface and a rough surface and has rustproof treatment layers on both surfaces. There is. According to the present invention, since the metal foil has the glossy surface and the rough surface, the thickness of the anticorrosion treatment layer provided when the anticorrosion treatment is applied thereon is different, and further the blackening treatment provided thereon. The layer thicknesses are also different. The rough surface side of the metal foil mesh is used as a ground portion by utilizing the difference in the thickness of the blackening treatment layer, which has excellent light transmittance and visibility, and prevents the generation of eddy currents in the metal foil mesh. You can get no electromagnetic wave shielding effect.

Further, the method for producing an electromagnetic wave shielding material of the present invention comprises a step of forming a metal foil mesh consisting of a glossy surface and a rough surface, and having both surfaces rust-proofed, into a single metal foil mesh; And a step of performing blackening treatment. According to the method for producing an electromagnetic shielding material of the present invention, by using the difference in the thickness of the rust preventive treatment layer on the glossy surface and the rough surface of the metal foil as the ground portion on the rough surface side of the metal foil mesh, It is possible to preferably manufacture an electromagnetic wave shielding material having the above-mentioned excellent light transmittance and visibility and having an excellent electromagnetic wave shielding effect that does not hinder the generation of eddy currents in the metal foil mesh.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The metal foil used in the electromagnetic wave shielding material of the present invention has a glossy surface and a rough surface, and both surfaces are rustproofed. The present invention makes it possible to partially blacken the metal foil mesh by utilizing the difference in the thickness of the anticorrosion treatment layer between the glossy surface and the rough surface of the metal foil.
The rough surface of the metal foil preferably has a roughness of 1 to 3 μm, whereby when the surface of the metal foil is subjected to rust-preventing treatment, a rust-preventing layer provided on the glossy surface and the rough surface. There is an effective difference in the thickness of the.

As the metal foil, a metal such as copper, iron, nickel, aluminum, gold, silver, platinum, or an alloy of two or more of these metals (for example, copper-nickel alloy, stainless steel, etc.) is formed by plating. Deposited in the shape of
Alternatively, a metal material such as the above metal, alloy, or metal compound is foiled by electrolysis, rolling, or the like, and the surface thereof is plated, and a foil having a glossy surface and a rough surface can be appropriately used. . In particular, a foil made of copper, iron, nickel, aluminum or an alloy thereof is preferable because it can be manufactured at low cost. The thickness is preferably as thin as possible, and is 5 to 50 μm, preferably 8 to 40 μm, and more preferably 10 to 25 μm.
Furthermore, the metal foil used in the present invention needs to be rust-proofed on both sides.

The anticorrosion treatment is a treatment mainly composed of chromium oxide formed by a single coating treatment of chromium oxide, a mixed coating treatment of chromium oxide and zinc and / or zinc oxide, or a combination thereof. The term "corrosion-preventing layer" means a layer obtained by these treatments. For the single coating of chromium oxide, either immersion chromate or electrolytic chromate may be used. The mixed film treatment of chromium oxide and zinc and / or zinc oxide is performed by electroplating using a plating bath containing zinc salt or zinc oxide and chromate, and It is a treatment for coating the rust preventive layer of the following zinc-chromium group mixture, which is called electrolytic zinc / chromium treatment. Further, a combination of a film treatment of chromium oxide alone and a mixed film treatment of chromium oxide and zinc and / or zinc oxide is also effective.

The method of manufacturing the electromagnetic wave shielding material of the present invention is
First, the rustproof metal foil is formed into a single metal foil mesh. The method of forming the metal foil into a single metal foil mesh is not particularly limited, but the following method of forming a photoresist layer on both surfaces of the metal foil is preferable because it can be easily obtained. The method of obtaining a single metal foil mesh is to form a photoresist layer on both sides of the metal foil by coating or laminating, etc., expose one side with a desired mesh pattern using a photomask, and leave the other side entirely. The exposure cures the entire layer. In forming the mesh pattern, it is not necessary to distinguish between the glossy surface side and the rough surface side of the metal foil. The thickness of the photoresist layer is preferably about 10 to 25 μm, and the irradiation amount of ultraviolet rays is preferably about 80 to 160 mJ. For the exposure of this mesh pattern, a printing means for directly irradiating the resist with laser light may be used instead of the irradiation of ultraviolet rays or the like using the above-mentioned mask.

Next, the mask is removed, and the resist is removed from the unexposed portion by immersing it in a treatment solution for resist removal such as an aqueous solution of sodium carbonate. As a result, the mesh pattern made of the resist of the exposed portion is developed on the surface of the metal foil on one surface, and the protective layer for the etching step is formed on the other surface. Next, for example, the metal foil of the portion corresponding to the undeveloped portion is etched by an etching means such as chemical etching in which the whole is immersed in an etching treatment solution in which ferric chloride is dissolved in hydrochloric acid, and then, a caustic soda diluting solution is used. The whole metal foil mesh is obtained by immersing the whole in a resist removing treatment solution such as the above, and removing the remaining developing portion and the resist used as the protective layer at once.

As the photoresist resin, various conventionally known photoresists can be used.
A photopolymerization type photosensitive resin is preferable, and specifically, a normally used photocurable composition containing a photopolymerizable monomer, a binder resin, a photopolymerization initiator and other auxiliary agents is preferably used. Of these, dry film resists of alkaline water developing type and the like are particularly preferable.

In the mesh pattern of the metal foil mesh of the present invention, the line width of the mesh pattern is 10 to 50 .mu.
m, preferably 15 to 30 μm, and the aperture ratio is 80% or more, preferably 85% or more. The opening ratio mentioned here means the total area of the holes with respect to the effective area of use of the metal foil. The width of the holes in the mesh pattern (pitch of the line portion) is suitably 100 to 500 μm, preferably 150 to 300 μm.

The mesh pattern is preferably a geometrical pattern, and the shape of the holes is appropriately selected from parallelograms such as squares and rectangles, circles or regular hexagons (honeycomb shape). Further, since it is essential that any part has a certain characteristic (mainly light transmitting property and electromagnetic wave shielding property), it is preferable that the parts are regularly arranged.

Next, the metal foil mesh obtained as described above is blackened. As the blackening treatment, oxidation treatment,
A method such as sulfurization treatment may be mentioned, but in the present invention,
The soft etching process for removing the rustproof film on the metal foil surface is not performed. Specifically, after washing both surfaces of the metal foil mesh having the rustproof layer with water, oxidation treatment with an aqueous solution of sodium hydroxide and sodium chlorite is performed at 70 to 80 ° C.
And the blackening treatment layer is formed on the surface of the metal foil mesh.

As shown in FIG. 1, the metal foil mesh of the electromagnetic wave shielding material manufactured as described above is composed of the ground portion 1 located at the peripheral portion and the mesh portion 2 surrounded by the ground portion 1. The glossy surface and the side surface are blackened, but the rough back surface is not blackened. That is, the back surface (rough surface) of the ground portion 1 is not blackened, and the mesh portion 2 has the glossy surface 3 and the side surface 4 which are blackened as shown in the sectional view of FIG. The back surface 5, which is the surface, is not blackened.

The fact that the back surface 5, which is a rough surface, is not blackened means that the back surface 5 is not blackened more than the front surface 3 and the side surface 4. If grounding is possible, it is a rough surface. A certain back surface 5 may also be blackened.

The electromagnetic wave shielding material produced by the present invention comprises at least the metal foil mesh as described above, and further comprises a transparent substrate, a function-imparting layer, and an adhesive or pressure-sensitive adhesive layer according to a conventionally known method. By providing, it is possible to develop various layer configurations. Hereinafter, members constituting the electromagnetic wave shielding material according to the present invention will be described in detail.

A. Transparent Substrate The transparent substrate used for the electromagnetic wave shielding material of the present invention has a refractive index (JIS K-7142) of 1.45.
Those in the range of 1.55 are desirable. Specific examples include polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyarylate, polyether,
Polycarbonate (PC), polysulfone, polyether sulfone, cellophane, aromatic polyamide, polyvinyl alcohol, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer ( ABS), polymethylmethacrylate (P
MMA), polyamide, polyacetal (POM), polyphenylene terephthalate (PPE), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide imide (PAI), polyether amide (PEI), polyether ether ketone (PEEK), Various resin films such as polyimide (PI) and polytetrafluoroethylene, and glass substrates such as quartz glass and soda glass can be preferably used. Among these, this electromagnetic wave shielding material is used for PDP and L
When used for CD, PET, PC and TAC are particularly preferable.

The higher the transparency of these transparent substrates, the better the light transparency, but the light transmittance (JIS C-6714) is preferably 80% or more, more preferably 90% or more. When the transparent substrate is used for a PDP, the transparent substrate is preferably a film because the surface glass of the PDP can be protected to prevent the glass from scattering when the surface of the PDP is impacted. The thickness of the transparent substrate is preferably thin from the viewpoint of weight reduction, but in view of its productivity, it is in the range of 1 to 700 μm, preferably 10 to
It is preferable to use one having a range of 200 μm.

Further, the transparent substrate is subjected to surface treatment such as alkali treatment, corona treatment, plasma treatment, fluorine treatment and sputtering treatment, coating with a surfactant or a silane coupling agent, or surface modification treatment such as Si vapor deposition. By performing the above, the adhesion between the function-imparting layer and the transparent substrate can be improved.

B. Function imparting layer The function imparting layer in the present invention may be any layer as long as it is a layer for imparting a specific function to the transparent substrate,
The following layers are specifically mentioned. (1) Antireflection Layer and Antiglare Layer For the antireflection layer and antiglare layer, it is possible to employ a bocas technique for scattering or diffusing light, as in frosted glass. That is, in order to scatter or diffuse light, it is basically necessary to roughen the light incident surface, and for this roughening treatment, the substrate surface is directly roughened by a sandblast method, an embossing method, or the like. Method, a method of providing a roughened layer containing an inorganic filler such as silica or an organic filler such as resin particles in a resin that is cured by radiation or heat or a combination on the surface of the substrate, and sea islands on the surface of the substrate. A method of forming a porous film having a structure can be mentioned.

As another method for forming the antireflection layer, a material having a high refractive index and a material having a low refractive index are alternately laminated to form a multi-layer (multi-coat), so that the reflection on the surface is suppressed, which is preferable. An antireflection effect can be obtained. Usually, this antireflection layer is formed by a vapor phase method or a sol-gel method in which a low refractive index material typified by SiO ₂ and a high refractive index material such as TiO ₂ and ZrO ₂ are alternately deposited. It is formed.

In order to improve the antireflection effect, the refractive index of the low refractive index layer is preferably 1.45 or less. As a material having these characteristics, for example, LiF
(Refractive index n = 1.4), MgF ₂ (n = 1.4), 3N
aF.AlF ₃ (n = 1.4), AlF ₃ (n = 1.
4), Na ₃ AlF ₆ (n = 1.33), SiO ₂ (n =
1.45) and other inorganic materials are finely divided into fine particles and incorporated into acrylic resin, epoxy resin, etc., low-reflecting inorganic materials, fluorine-based, silicone-based organic compounds, thermoplastic resins, thermosetting resins, radiation curing An organic low reflection material such as a mold resin can be used.

Further, it is also possible to use a material in which a sol in which ultrafine silica particles of 5 to 30 nm are dispersed in water or an organic solvent and a fluorine-based film forming agent are mixed. 5 to 3
A sol in which ultrafine silica particles of 0 nm are dispersed in water or an organic solvent is prepared by a method of dealkalizing alkali metal ions in an alkali silicate salt by ion exchange or a method of neutralizing the alkali silicate salt with a mineral acid. Known silica sol obtained by condensing known active silicic acid, known silica sol obtained by condensing alkoxysilane in an organic solvent in the presence of a basic catalyst with hydrolysis, and further in the above aqueous silica sol. An organic solvent-based silica sol (organo silica sol) obtained by substituting the water with an organic solvent by a distillation method or the like is used. These silica sols can be used both as an aqueous system and as an organic solvent system. It is not necessary to completely replace water with an organic solvent when producing an organic solvent-based silica sol. The silica sol is SiO
₂ contains 0.5 to 50% by weight of solid content.
The ultrafine silica particles in the silica sol may have various structures such as spherical, needle-like, and plate-like structures. Further, as the film forming agent, alkoxysilane, a hydrolyzate of a metal alkoxide or a metal salt, a fluorine-modified polysiloxane, or the like can be used.

The low refractive index layer is obtained by diluting the above-mentioned materials in a solvent, for example, a wet coating method such as spin coater, roll coating or printing, or a vapor phase method such as vacuum deposition, sputtering, plasma CVD or ion plating. It can be obtained by providing the layer on the high refractive index layer by a method, drying, and then curing it with heat or radiation (in the case of ultraviolet rays, a photopolymerization initiator is used).

In the high refractive index layer, a binder resin having a high refractive index is used to increase the refractive index, or ultrafine particles having a high refractive index are added to the binder resin, or they are used in combination. By doing. The refractive index of the high refractive index layer is preferably in the range of 1.55 to 2.70.

The resin used for the high refractive index layer is arbitrary as long as it is transparent, and thermosetting resin, thermoplastic resin, radiation (including ultraviolet) curable resin and the like can be used. As the thermosetting resin, phenol resin, melamine resin, polyurethane resin, urea resin, diallyl phthalate resin, guanamine resin, unsaturated polyester resin, aminoalkyd resin, melamine-urea co-condensation resin, silicon resin, polysiloxane resin, etc. These resins can be used, and if necessary, a crosslinking agent, a curing agent such as a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier, etc. can be added.

As ultrafine particles having a high refractive index, for example, ZnO, which can also provide an ultraviolet shielding effect, is used.
(Refractive index n = 1.9), TiO ₂ (n = 2.3 to ₂ .
7), fine particles of CeO ₂ (n = 1.95), or SnO ₂ (n = 1.9) doped with antimony, which has an antistatic effect and can prevent dust from adhering.
5) or ITO (n = 1.95) fine particles. Other fine particles include Al ₂ O ₃ (n = 1.6
3), La ₂ O ₃ (n = 1.95), ZrO ₂ (n = 2.
05), Y ₂ O ₃ (n = 1.87) and the like. These ultrafine particles are used alone or as a mixture,
Colloidal particles dispersed in an organic solvent or water are good in terms of dispersibility, and have a particle size of 1
-100 nm, preferably 5-20 from the transparency of the coating film.
nm is desirable.

To provide the high refractive index layer, the above-mentioned materials are diluted with, for example, a solvent, provided on a substrate by a method such as a spin coater, a roll coater, or printing and dried, and then heat or radiation (in the case of ultraviolet rays) May be cured with a photopolymerization initiator) or the like.

(2) Near-infrared ray blocking layer The near-infrared ray blocking layer is formed by a wet coating method such as roll coating or printing of a material that absorbs near-infrared rays (near-infrared ray absorbing material), vacuum deposition, sputtering, plasma CVD, ion plating. It is formed by a vapor phase method such as coating. As a material that absorbs near infrared rays, a metal sulfide and a thiourea compound, a phthalocyanine-based near infrared absorbent, a metal complex-based near infrared absorbent, a copper compound bisthiourea compound, a phosphorus compound and a copper compound, indium oxide,
Examples thereof include metal oxide films such as tin oxide, titanium dioxide, cerium oxide, zirconium oxide, zinc oxide, tantalum oxide, niobium oxide, and zinc sulfide.

(3) Antistatic Layer The antistatic layer is formed by depositing a metal such as aluminum or tin or a metal oxide film such as ITO by an extremely thin film by vapor deposition, sputtering, or the like, metal fine particles such as aluminum or tin, whiskers, or tin oxide. Transfer between fine particles or whiskers, 7,7,8,8-tetracyanoquinodimethane doped with antimony and other metal oxides, and electron donors such as metal ions and organic cations A method in which a complexed filler or the like is dispersed in polyester resin, acrylic resin, epoxy resin or the like and provided by solvent coating, or a method in which polypyrrole, polyaniline or the like doped with camphor sulfonic acid or the like is provided by solvent coating or the like is used. Can be provided. The transmittance of the antistatic layer is preferably 80% or more for optical use.

(4) Hard coat layer As the hard coat layer, one formed of an inorganic or organic resin for a hard coat layer is used.
Urethane (meth) acrylate, polyester (meth)
Examples thereof include polyfunctional polymerizable compounds containing two or more acryloyl groups and methacryloyl groups such as acrylates and polyether (meth) acrylates, which are polymerized and cured by active energy rays such as ultraviolet rays and electron beams.

(5) Colored light correction layer In the PDP, LCD, etc., a layer for correcting the color development on the image is provided. In other words, this colored light correction layer serves as a visible filter and a shielding filter,
Layers are formed by dyes and pigments. As the dye used here, azomethine-based, squarylium-based, cyanine-based, oxonol-based, anthraquinone-based, azo-based,
Examples thereof include benzylidene compounds.

(6) Antifouling layer The antifouling layer is a layer exhibiting antifouling property by controlling the critical surface tension to 20 dyn / cm or less. When the critical surface tension of this layer is larger than 20 dyn / cm, it becomes difficult to remove stains attached to the surface. As the material for the antifouling layer, a radiation curable resin can be preferably used, and among them, a fluorine-based fluorine-containing material is particularly preferable in terms of preventing stains.

As the above-mentioned fluorine-containing material, a vinylidene fluoride copolymer, a fluoroolefin / hydrocarbon copolymer, which is soluble in an organic solvent and is easy to handle,
Fluorine-containing epoxy resin, fluorine-containing epoxy acrylate, fluorine-containing silicone, fluorine-containing alkoxysilane,
Furthermore, TEFRON (registered trademark) AF1600 (made by DuPont, refractive index n = 1.30), CYTOP (made by Asahi Glass Co., Ltd. n = 1.34), 17FM (manufactured by Mitsubishi Rayon Co., Ltd. n = 1.35). ), Opstar JN-72
12 (manufactured by Japan Synthetic Rubber Co., Ltd. n = 1.40), LR
201 (manufactured by Nissan Chemical Industries, Ltd., n = 1.38). These may be used alone or in combination of two or more.

Further, 2- (perfluorodecyl) ethyl methacrylate, 2- (perfluoro-7-methyloctyl) ethyl methacrylate, 3- (perfluoro-7)
-Methyloctyl) -2-hydroxypropyl methacrylate, 2- (perfluoro-9-methyldecyl) ethyl methacrylate, 3- (perfluoro-8-methyldecyl) -2-hydroxypropyl methacrylate, and other fluorine-containing methacrylates, 3-perfluoro Octyl-2
-Hydroxypropyl acrylate, 2- (perfluorodecyl) ethyl acrylate, 2- (perfluoro-)
Fluorine-containing acrylate such as 9-methyldecyl) ethyl acrylate, 3-perfluorodecyl-1,2-epoxypropane, 3- (perfluoro-9-methyldecyl)
Epoxide such as -1,2-epoxypropane, radiation-curable fluorine-containing monomer such as epoxy acrylate,
Examples thereof include oligomers and prepolymers. These may be used alone or in combination of two or more.

However, although these are excellent in antifouling property, they have poor wetting property, and therefore, depending on the composition, there is a possibility of causing a problem of repelling the antifouling layer on the substrate or a problem of peeling of the antifouling layer from the substrate. There is. Therefore, when these are used, a monomer, oligomer, or prepolymer having a polymerizable unsaturated bond such as acryloyl group, methacryloyl group, acryloyloxy group, or methacryloyloxy group used as a radiation curable resin is appropriately mixed and used. Is desirable.

C. Adhesive or pressure-sensitive adhesive layer As the adhesive or pressure-sensitive adhesive layer, polyethyl acrylate, polybutyl acrylate, poly-2-ethylhexyl acrylate, poly-t-butyl acrylate, poly-3-ethoxypropyl acrylate, polyoxycarbonyl tetramethacrylate. , Polymethyl acrylate, polyisopropyl methacrylate, polydodecyl methacrylate, polytetradecyl methacrylate, poly-n-propyl methacrylate, poly-3,3,5-trimethylcyclohexyl methacrylate, polyethyl methacrylate, poly-2-nitro-2-methyl Propyl methacrylate, polytetracarbanyl methacrylate, poly-1,1-diethylpropyl methacrylate,
Mention may be made of poly (meth) acrylic acid esters such as polymethylmethacrylate.

Natural rubber, polyisoprene, poly-
1,2-butadiene, polyisobutene, polybutene, poly-2-heptyl-1,3-butadiene, poly-2-t
-(Di) enes such as butyl-1,3-butadiene and poly-1,3-butadiene, polyethers such as polyoxyethylene, polyoxypropylene, polyvinyl ethyl ether, polyvinyl hexyl ether and polyvinyl butyl ether, polyvinyl acetate Examples thereof include polyesters such as polyvinyl propionate, polyurethane, ethyl cellulose, polyvinyl chloride, polyacrylonitrile, polymethacrylonitrile, polysulfone, polysulfide, and phenoxy resin.

Further, bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetrahydroxyphenylmethane type epoxy resin, novolac type epoxy resin, resorcin type epoxy resin, polyalcohol / polyglycol type epoxy resin, polyolefin type epoxy resin, oil There may be mentioned epoxy resins such as cyclic and halogenated bisphenols. If necessary, two or more kinds of these resins may be copolymerized, or two or more kinds may be mixed and used.

Examples of the curing agent for the adhesive include amines such as triethylenetetramine, xylenediamine, diaminodiphenylmethane, phthalic anhydride, maleic anhydride, dodecylsuccinic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride. An acid anhydride, diaminodiphenyl sulfone, tris (dimethylaminomethyl) phenol, polyamide resin, dicyandiamide, ethylmethylimidazole and the like can be used. If necessary, the resin composition of the adhesive used in the present invention may contain additives such as a diluent, a plasticizer, an antioxidant, a filler and a tackifier.

[0044]

EXAMPLES Next, examples of the present invention and comparative examples to the present invention will be shown to further clarify the effects of the present invention. <Example 1> A 25 μm thick copper foil having a rust preventive layer of chromium oxide, one surface of which is a rough surface having a roughness of 3 μm and the other surface of which is a glossy surface, is provided with 25 μm photoresist layers on both surfaces. After laminating, a mask on which a predetermined mesh pattern is printed as a light-transmitting portion is laminated on one surface of the photoresist layer, and 100 is applied from both surfaces of the photoresist layer.
It was irradiated with mJ ultraviolet rays. Next, the mask was removed, and the resist in the unexposed portion was removed by immersing in a sodium carbonate aqueous solution. As a result, the mesh pattern was developed on one surface, and the protective layer for the etching step was formed on the other surface. Then, the metal foil of the portion corresponding to the undeveloped area is etched by immersing it in a hydrochloric acid solution of ferric chloride, and then the remaining developed area and the resist used as the protective layer are removed at once, and the metal foil mesh is used alone. Was produced.

Next, the metal foil mesh simple substance is dipped in an aqueous solution of sodium hydroxide and sodium chlorite to obtain 80
Blackening treatment was performed at 10 ° C. for 10 minutes to obtain a blackened metal foil mesh simple substance whose rough surface was not blackened as shown in FIG.

Then, the above blackened metal foil mesh simple substance is coated with a curable adhesive so that the thickness after drying becomes 20 μm to form an adhesive layer, and a transparent PE having a thickness of 75 μm is formed.
After being pressure-bonded to one side of the T film, it was cured at 60 ° C. for 3 days to manufacture an electromagnetic wave shielding material of Example 1 of the present invention.

<Comparative Example 1> In the same manner as in Example 1 except that a copper foil having glossy surfaces on both sides was used.
The electromagnetic wave shield material of Comparative Example 1 was manufactured. The entire surface of the metal foil mesh in the electromagnetic wave shield material of Comparative Example 1 was blackened.

Regarding Example 1 and Comparative Example 1 obtained as described above, a spectrum analyzer TR-4172 manufactured by ADVANTEST (evaluation part: TR-17
301), the degree of shielding electromagnetic waves at 500 MHz was measured to evaluate the electromagnetic wave shielding effect.

As a result, in the metal foil mesh of Example 1 having the ground portion using the metal foil having the glossy surface and the rough surface, the electromagnetic wave shielding degree was -57 dB, which showed a good electromagnetic wave shielding effect. On the other hand, in the metal foil mesh of Comparative Example 1 using the metal foil having glossy surfaces on both sides and having no ground portion, the electromagnetic wave shielding degree was −48 dB, and the electromagnetic wave shielding effect was inferior.

[0050]

As described above, the electromagnetic wave shielding material of the present invention has an excellent electromagnetic wave shielding effect, and the method of producing the electromagnetic wave shielding material of the present invention does not use a masking method or the like, and the metal foil is not used. It is possible to partially blacken the mesh, and it is possible to manufacture an electromagnetic wave shielding material having excellent light transmittance and visibility and an excellent electromagnetic wave shielding effect in a simple process.

[Brief description of drawings]

FIG. 1 is a schematic view of a metal foil mesh of an electromagnetic wave shielding material manufactured according to the present invention.

FIG. 2 is an enlarged sectional view of a part of a mesh portion of the metal foil mesh shown in FIG.

[Explanation of symbols]

10 ... Metal foil mesh, 1 ... Ground part, 2 ... Mesh part, 3 ... Front surface, 4 ... Side surface, 5 ... Back surface.

Claims (4)

[Claims] 1. An electromagnetic wave shield material comprising a blackening treatment layer on the surface of a metal foil mesh having a glossy surface and a rough surface and having antirust treatment layers on both surfaces. 2. A method comprising: a step of forming a metal foil mesh having a lustrous surface and a rough surface and having both surfaces rust-proofed into a single metal foil mesh; and a step of blackening the metal foil mesh. And a method for manufacturing an electromagnetic wave shielding material. 3. The method for producing an electromagnetic wave shield material according to claim 2, wherein the blackening treatment is performed at 70 to 80 ° C. 4. The method for manufacturing an electromagnetic wave shield material according to claim 2, wherein the rough surface of the metal foil has a roughness of 1 to 3 μm.